verity: pull up maybe_read_entry
Since the latest refactoring it is now possible to pull up maybe_read_entry.
I also removed the PENDING flag and instead just call is_populated.
BUG=chromium-os:13872
TEST=Ran dm-verity.git unit tests. Ran platform_DMVerityCorruption on H/W.
kernel.git Review URL: http://codereview.chromium.org/6883252
TBRing since already LGTMed and committed to kernel.git
Change-Id: Ie9a60325b8a1f4d40325cd0211477551c9aed488
Reviewed-on: http://gerrit.chromium.org/gerrit/4278
Reviewed-by: Mandeep Singh Baines <msb@chromium.org>
Tested-by: Mandeep Singh Baines <msb@chromium.org>
diff --git a/dm-bht.c b/dm-bht.c
index 7467455..a9968c0 100644
--- a/dm-bht.c
+++ b/dm-bht.c
@@ -459,70 +459,6 @@
}
EXPORT_SYMBOL(dm_bht_write_completed);
-/* dm_bht_maybe_read_entry
- * Attempts to atomically acquire an entry, allocate any needed
- * memory, and issues the I/O callback to load the hash from disk.
- * Return value is negative on error. When positive, it is the state
- * value.
- */
-static int dm_bht_maybe_read_entry(struct dm_bht *bht, void *ctx,
- unsigned int depth, unsigned int index)
-{
- struct dm_bht_level *level = &bht->levels[depth];
- struct dm_bht_entry *entry = &level->entries[index];
- sector_t current_sector = level->sector + to_sector(index * PAGE_SIZE);
- struct page *node_page;
- int state;
-
- BUG_ON(depth >= bht->depth);
-
- /* XXX: hardcoding PAGE_SIZE means that a perfectly valid image
- * on one system may not work on a different kernel.
- * TODO(wad) abstract PAGE_SIZE with a bht->entry_size or
- * at least a define and ensure bht->entry_size is
- * sector aligned at least.
- */
-
- /* If the entry's state is UNALLOCATED, then we'll claim it
- * for allocation and loading.
- */
- state = atomic_cmpxchg(&entry->state,
- DM_BHT_ENTRY_UNALLOCATED,
- DM_BHT_ENTRY_PENDING);
- DMDEBUG("dm_bht_maybe_read_entry(d=%u,ei=%u): ei=%lu, state=%d",
- depth, index, (unsigned long)(entry - level->entries), state);
-
- if (state != DM_BHT_ENTRY_UNALLOCATED)
- goto out;
-
- state = DM_BHT_ENTRY_REQUESTED;
-
- /* Current entry is claimed for allocation and loading */
- node_page = (struct page *) mempool_alloc(bht->entry_pool, GFP_NOIO);
- if (!node_page)
- goto nomem;
- /* dm-bht guarantees page-aligned memory for callbacks. */
- entry->nodes = page_address(node_page);
-
- /* TODO(wad) error check callback here too */
- DMDEBUG("dm_bht_maybe_read_entry(d=%u,ei=%u): reading %lu",
- depth, index, (unsigned long)(entry - level->entries));
- bht->read_cb(ctx, current_sector, entry->nodes,
- to_sector(PAGE_SIZE), entry);
-
-out:
- if (state <= DM_BHT_ENTRY_ERROR)
- DMCRIT("entry %u is in an error state", index);
-
- return state;
-
-nomem:
- DMCRIT("failed to allocate memory for entry->nodes from pool");
- return -ENOMEM;
-
-
-}
-
/* dm_bht_verify_path
* Verifies the path. Returns 0 on ok.
*/
@@ -716,13 +652,18 @@
for (i = 0; i < level->count; i++, entry++) {
unsigned int count = bht->node_count;
+ struct page *pg;
- r = dm_bht_maybe_read_entry(bht, read_cb_ctx, depth, i);
- if (r < 0) {
+ pg = (struct page *) mempool_alloc(bht->entry_pool,
+ GFP_NOIO);
+ if (!pg) {
DMCRIT("an error occurred while reading entry");
goto out;
}
+ entry->nodes = page_address(pg);
+ atomic_set(&entry->state, DM_BHT_ENTRY_READY);
+
if (i == (level->count - 1))
count = child_level->count % bht->node_count;
if (count == 0)
@@ -827,38 +768,63 @@
/**
* dm_bht_populate - reads entries from disk needed to verify a given block
* @bht: pointer to a dm_bht_create()d bht
- * @read_cb_ctx:context used for all read_cb calls on this request
+ * @ctx: context used for all read_cb calls on this request
* @block_index:specific block data is expected from
*
- * Returns negative value on error.
+ * Returns negative value on error. Returns 0 on success.
*/
-int dm_bht_populate(struct dm_bht *bht, void *read_cb_ctx,
+int dm_bht_populate(struct dm_bht *bht, void *ctx,
unsigned int block_index)
{
- unsigned int depth, entry_index;
- int status, populated = 0;
+ unsigned int depth;
+ int state = 0;
BUG_ON(block_index >= bht->block_count);
DMDEBUG("dm_bht_populate(%u)", block_index);
for (depth = 0; depth < bht->depth; ++depth) {
- entry_index = dm_bht_index_at_level(bht, depth, block_index);
- status = dm_bht_maybe_read_entry(bht, read_cb_ctx, depth,
- entry_index);
- if (status < 0)
- goto read_error;
+ struct dm_bht_level *level;
+ struct dm_bht_entry *entry;
+ unsigned int index;
+ struct page *pg;
- /* Accrue return code flags */
- populated |= status;
+ entry = dm_bht_get_entry(bht, depth, block_index);
+ state = atomic_cmpxchg(&entry->state,
+ DM_BHT_ENTRY_UNALLOCATED,
+ DM_BHT_ENTRY_PENDING);
+
+ if (state <= DM_BHT_ENTRY_ERROR)
+ goto error_state;
+
+ if (state != DM_BHT_ENTRY_UNALLOCATED)
+ continue;
+
+ /* Current entry is claimed for allocation and loading */
+ pg = (struct page *) mempool_alloc(bht->entry_pool, GFP_NOIO);
+ if (!pg)
+ goto nomem;
+
+ /* dm-bht guarantees page-aligned memory for callbacks. */
+ entry->nodes = page_address(pg);
+
+ /* TODO(wad) error check callback here too */
+
+ level = &bht->levels[depth];
+ index = dm_bht_index_at_level(bht, depth, block_index);
+ bht->read_cb(ctx, level->sector + to_sector(index * PAGE_SIZE),
+ entry->nodes, to_sector(PAGE_SIZE), entry);
}
- return populated;
+ return 0;
-read_error:
- DMCRIT("failure reading entry %u depth %u", entry_index, depth);
- return status;
+error_state:
+ DMCRIT("block %u at depth %u is in an error state", block_index, depth);
+ return state;
+nomem:
+ DMCRIT("failed to allocate memory for entry->nodes from pool");
+ return -ENOMEM;
}
EXPORT_SYMBOL(dm_bht_populate);
diff --git a/dm-bht.h b/dm-bht.h
index 21d5e34..44a1c02 100644
--- a/dm-bht.h
+++ b/dm-bht.h
@@ -25,9 +25,6 @@
#define DM_BHT_ENTRY_VERIFIED 8 /* 'nodes' has been checked against parent */
#define DM_BHT_ENTRY_READY 4 /* 'nodes' is loaded and available */
#define DM_BHT_ENTRY_PENDING 2 /* 'nodes' is being loaded */
-#define DM_BHT_ENTRY_REQUESTED 1 /* non-state response indicating entry is
- * pending because of the current call
- */
#define DM_BHT_ENTRY_UNALLOCATED 0 /* untouched */
#define DM_BHT_ENTRY_ERROR -1 /* entry is unsuitable for use */
#define DM_BHT_ENTRY_ERROR_IO -2 /* I/O error on load */
diff --git a/dm-bht_unittest.cc b/dm-bht_unittest.cc
index 396b446..3725009 100644
--- a/dm-bht_unittest.cc
+++ b/dm-bht_unittest.cc
@@ -140,7 +140,7 @@
EXPECT_GE(dm_bht_populate(bht_.get(),
reinterpret_cast<void *>(this),
blocks),
- DM_BHT_ENTRY_REQUESTED);
+ DM_BHT_ENTRY_PENDING);
// Since we're testing synchronously, a second run through should yield
// READY.
EXPECT_GE(dm_bht_populate(bht_.get(),
